Multiwfn forum / Does the given reaction need BSSE correction?

Re: Does the given reaction need BSSE correction?

dummy@example.com (saeed_E) — Mon, 18 Dec 2023 14:04:35 +0000

Your clear and straightforward comments are highly appreciated.

Saeed

Re: Does the given reaction need BSSE correction?

dummy@example.com (sobereva) — Mon, 18 Dec 2023 12:15:42 +0000

As long as the studied reaction involves change of weak interaction, one should pay attention to BSSE problem. If the basis set is sufficiently large such as def2-QZVP, or 3-zeta basis set with rich diffuse functions such as aug-cc-pVTZ, then correction for BSSE effect is not quite needed. In the present situations, counterpoise correction evidently complicates the study, so I recommend simply using def2-QZVP or aug-cc-pVTZ and then simply ignored the annoying BSSE problem.

Re: Does the given reaction need BSSE correction?

dummy@example.com (saeed_E) — Sun, 17 Dec 2023 20:45:15 +0000

Dear Tian,
Too many thanks for your highly valuable and informative comments. Please, also, let me explain another issue. Indeed, if these exchange reaction is considered as follows:

Acroleine-BF3 complex...nitrone---->nitrone-BF3 complex...Acroleine

Then, BSSE correction is unavoidable. In other words, all reactants and products should be considered as whole complex very similar to what happen during an SN2 reaction. I think the provided exchange reaction as portrayed in the first question does not need BSSE correction whether a large or a small basis set is employed.

Sincerely,
Saeed

Re: Does the given reaction need BSSE correction?

dummy@example.com (sobereva) — Sun, 17 Dec 2023 18:47:13 +0000

If def2-QZVP or aug-cc-pVTZ is used, BSSE problem is small enough to be safely ignored.

Does the given reaction need BSSE correction?

dummy@example.com (saeed_E) — Sat, 16 Dec 2023 18:33:46 +0000

Dear Tian,
Please assume BF3 interacts with acroleine as a dipolarophile to form acroleine-BF3 complex. Then, a 1,3dipole such as simplest nitrone is added to this complex so a 1,3DC reaction takes place. Evidently, in addition to the 1,3DC reaction, an exchange reaction can compete in which BF3 is separated from acroleine and bound to nitrone as:

Acroleine-BF3 complex+nitrone--->nitrone-BF3 complex+Acroleine

The challenging issue is that this exchange reaction really needs BSSE correction?

Sincerely,
Saeed